Continents, plate tectonics and life make our Earth unique in the solar system and perhaps, in
the entire universe (so far). However, none of them was present when the planet formed some 4.56
billion years ago (Ga). Therefore, understanding how, when, and why they appeared is critical to
understand planetary evolution and habitability. My work directly deals with these questions. For the
past few years, I am working on elucidating in what form plate tectonics appeared on the early Earth
(> 2 Ga) and what imprints it left on the different system components of the planet (e.g., lithosphere,
mantle, atmosphere etc.). In the talk, I will show how I find answers to these questions by integrating
field geology and petrology with the novel methods like diffusion modelling of micron-scale
compositional zonings in minerals to unravel geological timescales (diffusion chronometry) and
numerical modelling of large-scale tectonics. My work has revealed that plate tectonics processes
were substantially different > 2 Ga from their modern nature and, for the first time, showed how
timescales of large-scale processes can help us identify it from the natural rock record. I proposed a
new style of continent-continent collision (called peel-back orogenesis) for that time period, which is
found to have major implications for building and recycling Archean continental crust. While I continue
to work on these aspects, I have further extended my research to understand how deep and shallow
Earth processes were linked in ‘deep time’ (> 3 Ga). My interest is to see how and why ‘continental dry
land’ formed since it is pivotal in controlling atmospheric and oceanic chemistry, and climate.